The development and progression of various forms of arthritis is being investigated in an American Indian population. The patternso of joint disease will be examined to determine if distinctive patterns of degenerative joint disease can be recognized, and if so, their evolution and outcome will be followed. In addition, the prognostic significance of various factors related to rheumatoid arthritis and ankylosing spindylitis will be examined. The study which include clinical, radiographic and serologic studies of joint disease is part of a prospective study of the Gila River Indian Community, in which studies of diabetes mellitus and related diseases are being undertaken.